[Qgis-user] Field calculator regexp_substr.

[Fernando M. Roxo da Motta]

On Thu, 5 Nov 2015 20:14:22 -0200, "Fernando M. Roxo da Motta"
<petro at roxo.org> wrote:

  Sorry to answer to myself,


  I continued to try and (almost accidentally) I found that I need to
use the "memory" (the parenthesis) to define what is the desired
substring:

   to_int( regexp_substr( "Label", '([0-9]{1,})'))

  I found it when an expression like:

   
  regexp_substr( 'abd123de45', '.*([0-9]{1,}).*')

Returned the expected 123.  when I removed the ".*" and the "memory" it
returned nothing.


  Sorry to bother.


  Thanks anyway.


> 
> 
>   Hi all,
> 
> 
>   I have a shapefile with a string field (Label) with a content like
> "Line '15'", a text string (without the double quotes).  I want to
> create a new numeric field containing the value in the string field.
> 
>   I was able to create it using the function:
> 
>   to_int( regexp_replace( "Label", '.*([0-9]{1,}).*', '\\1''))
> 
>   I noticed that there is a function "regexp_substr", if I understood
> correctly, I should be able to use this just specifying the regex of
> the desired substring.  I hoped to be able to use:
> 
>    to_int( regexp_substr( "Label", '[0-9]{1,}'))
> 
> The return are just empty strings.    Am I missing something?
> 
>   BTW, I am using Qgis 2.12.0-Lyon on Xubuntu 14.04 64 bits.
> 
> 
>   Best regards.
> 
> 
> 
>   Roxo
> 








  Roxo

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